Mesoscale Discussion 1091
NWS Storm Prediction Center Norman OK
1114 AM CDT Mon Jun 19 2017
Areas affected...Much of central and eastern Maryland/Virginia
Concerning...Severe potential...Watch likely
Valid 191614Z - 191815Z
Probability of Watch Issuance...95 percent
SUMMARY...Increasing thunderstorm development appears likely during
the next few hours, and may begin impacting the Baltimore/Washington
D.C. metropolitan areas by 2-4 PM EDT.
DISCUSSION...Thunderstorm development is now underway along and
southeast of the Allegheny Mountains, as far south as the eastern
West Virginia panhandle. This appears to coincide with the
southeastern periphery of the stronger mid-latitude latitude
westerlies, which may gradually edge toward the Baltimore/Washington
D.C. metropolitan areas toward the 18-20Z time frame. As the
increasingly weakly capped moist boundary layer continues to
destabilize with additional insolation, this is expected to result
in increasing and intensifying thunderstorm development. In the
presence of 30-40 kt south to southwesterly mean lower/mid
tropospheric flow, heavy precipitation loading and downward momentum
transfer are expected to slowly lead to increasing potential for
downbursts.
Farther to the east and south, into parts of the Carolina piedmont
and Mid Atlantic coastal plain, where mid-level heights remain
fairly high and flow appears a bit weaker, but at least broadly
cyclonic, a general increase in thunderstorm development and
intensity appears probable through late afternoon.
..Kerr/Hart.. 06/19/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PHI...AKQ...LWX...RAH...RNK...
LAT...LON 36957987 37517948 39197779 39547720 39577594 38577558
37067687 36067831 36127965 36957987